Investigation of the effects of calcination temperature on the structure of LaMgAl11O19 for thermal barrier coating applications

摘要

Yttria Stabilized Zirconia (YSZ) is the most common thermal barrier coating material with a temperature tolerance up to 1200°C above which it undergoes phase transitions deteriorating its thermo-mechanical properties. Apart from YSZ, oxides having the complex Magnetoplumbite structure such as LaMgAlO are potential candidates for even higher temperature applications due to their thermo-physical properties. In this work, LaMgAlO was synthesized through sol-gel citric acid method using nitrate precursors. The powders were subjected to calcination treatment for 5 hours at 1000 °C, 1100 °C, 1200 °C, 1300 °C and 1400 °C. The microstructure was analyzed by XRD and SEM techniques. XRD results identified a pure single phase of LaMgAlO, obtained successfully at 1200 °C. Effects arising from changing calcination temperature show that lattice strain reduced and crystallite size increased with increase in temperature. SEM results revealed that the platelet structure of LaMgAlO was obtained which could increase thermal tolerance.